A granular inorganic cation-exchanger selective to cesium

The investigation results on the structure, sorptive-selective properties and exchange reversibility of the adsorbent selective to cesium cations are presented in this paper. A trade mark of this adsorbent is Termoxid-35. The composition of Termoxid-35 is the 'mixed' nickel ferrocyanide distributed over zirconium hydroxide as an inorganic carrier. The structure of the cation-exchanger was studied by the infrared spectroscopy and the X-ray diffraction, differential-thermal and thermo-gravimetric analyses. The adsorbent is the double-phase system consisting of a highly-dispersed amorphous phase of zirconium hydroxide and a micro-crystalline phase of mixed nickel ferrocyanide. The isotherms of cesium cation adsorption in the pH region of 6.2 to 9.6 in the presence of 1 mol/l NaCl are presented. The distribution coefficient for cesium in the Henry region increases with the pH of the solution and reaches 6.5x10⁵ cm³/g at pH=9.6. The distribution coefficient for cesium is more than 1.0x10⁴ cm³/g with the concentration of the cation in the solid phase of 0.1 mmol/g. The cesium cation sorption on the ion-exchanger is irreversible. (author)